1. Field of Invention
This invention relates to radiation cross-linkable ethylene-chlorotrifluoroethylene and ethylene-tetrafluoroethylene copolymer compositions.
2. Description of the Prior Art
It has heretofore been proposed to irradiate ethylene-chlorotrifluoroethylene copolymers and ethylene-tetrafluoroethylene copolymers to improve tensile strength as well as other properties at elevated temperatures. The proposed ionizing radiation includes X-rays, gamma rays, electron beams and the like. It has also been proposed to incorporate a small amount of a cross-linking promoter such as triallyl cyanurate into the copolymer prior to irradiation to reduce the irradiation dosage required to provide improved mechanical properties.
In our copending U.S. application Ser. No. 327,907, filed Jan. 20, 1973, there is disclosed melt-processable, radiation cross-linkable ethylene-chlorotrifluoroethylene copolymer compositions which contain, in weight percentages based upon the weight of the copolymer, about 0.1 to 5% of a radiation cross-linking promoter, about 0.1 to 5% of an anti-oxidant, and about 0.1 to 30% of an acid scavenger. Such compositions give off minimum odor when irradiated to cross-link the copolymer and do not develop bubbles subsequent to irradiation. Among the cross-linking promoters described therein are diallyl terephthalate and diallyl isophthalate.